Discovery - disabling onboard peripherals

Hi,
Bit of a noob question here, but I'm planning to use a STM32F4DISCOVERY board purely for its onboard programmer and also to save space on my PCB (will connect via header).
Unfortunately this means i get a bunch of things i don't really want connected to my chip - accelerometer, mic, audio DAC, etc.

I have ADC/USART connections which i wish to make, but some of these pins are already connected to the peripherals.
Question is, can I disable these peripherals or do I need to cut the trace? I dont actually have the board yet.

For example from the schematic I see ADC PC3 (ADC123_IN13) is connected to a whole bunch of resistors and caps for the audio module. This will obviously effect my reading.
Probably USART3 is the easiest to get to and only has a green LED on PD12 (USART3_RTS), will this effect its performance?

What do other people do? Or should I just put the cpu on my pcb and buy an external programmer?

Thanks for your help. I'm guessing i'll need to cut the traces but just wondering if there's an easier way.

The easiest route is to pick unused pins. Next is to find ones that don't conflict, or can be shared. Finally just desolder unwanted parts and remove them.

Part of the trick with designing with the STM32 series is to figure out what peripherals you want to escape, and what combinations will work. You won't be able to get the entire peripheral set out.

USART3 is probably the most useful to escape from the board, as it supports the System Loader for programming blank chips.

Check on places like eBay for STM32F2 or F4 boards that just escape chip pins to headers. They are often more expensive than the Discovery boards, but a whole lot cheaper than spinning a PCB design.

The ST-Discovery boards are cheap and aimed at quick mash-up or prototype work, given the low cost it's hard to feel guilty about hacking parts off them, or tacking on other boards, sockets, or connectors.